I imagine this has a simple answer. The default install comes with a label called custom2: {Width}x{Height} - {Size KB}. I'd like the size in MB, but when I changed the K to M that doesn't work. Any thoughts?

Thank-you. That didn't help, but it helped me understand things a little better. It turns out that what I was looking for was size(auto) which shows MB when the file is bigger than 1 MB and KB when smaller.